Проблема с валидацией формы update в Thymeleaf и Spring

<form method="POST" th:action="@{/accounts/addAccount/{id}(id=${client.id})}" th:object="${newAccount}">
<label for="sum">Сумма: </label>
<input type="text" th:field="*{sum}" name="sum"/><br/>
<div th:if="${#fields.hasErrors('sum')}" th:errors="*{sum}">Name Error</div>
<input type="submit" value="Add"/>
</form>

@PostMapping("/addAccount/{id}")
    public String addNewAccount(@ModelAttribute("newAccount") @Valid Account account,BindingResult result,@PathVariable Long id, Model model) {
        if(result.hasErrors()) {
             Client client = clientService.findClientById(id);
             model.addAttribute("client", client);
             return "addAccount";
            }
         else {
             Client client = clientService.findClientById(id);
             account.setClient(client);
             accountService.save(account);
    return "redirect:/accounts/{id}";
    }

@ModelAttribute("account")
    public Account newAccount(@RequestParam(required=false,value = "id") Long id){
        if (id == null) {
        return new Account();
        }
        else return accountService.findAccountById(id);
      }